Virus:

The white butterfly (Pieris rapae) is attacked by a virus to such an extent that it plays an important part in field control of this pest.

Bacteria:

Naturally occurring bacterial diseases materially help to control the diamond-back moth (Plutella maculipennis).

Fungi:

Fungi play a role in control of the diamond-back moth. The fungal parasites of the genus Cordyceps attack subterranean grass caterpillars and other hepialid caterpillars and change the body of the caterpillars into the so called “vegetable caterpillars”.

Nematodes:

These are of no importance as yet in New Zealand but are known to attack grass grubs (Costelytra zealandica).